How to define rulesets in Views Bulk Operations Module?

According to http://groups.drupal.org/node/14253 VBO should detect rule sets automatically and make them available in the list of operations to bulk operate -- but I just can't find my sets.

My guess is that this worked some time ago, but has been broken somehow. (I vaguely recall that I've invoked rule sets from VBO som six months ago or so, and the example rule set is there in the VBO list.)

My install is fresh:
* Drupal 6.15
* Rules 6.x-1.1
* VBO 6.x-1.9

That this should work is confirmed by a description on the VBO project page: http://drupal.org/project/views_bulk_operations
Is this a bug belonging to VBO, rather than Rules?

//Johan Falk, Sweden

It seems the answer to this question lies in Views Bulk Operations, not in Rules.
In the VBO file ruleset.action.inc (http://library.acquia.com/api/function/views_bulk_operations_ruleset_act...) the function to include rulesets checks that the rule set has one parameter (argument) only, to match it with the Views style.

line 8:
    if (count($ruleset['arguments']) == 1) { // For now, we only accept rulesets with one parameter (taken to be the 'type')

I tried creating a few rule sets, and those that had one argument only appeared nicely in the list.
I guess it would be pretty tricky to invoke a rule set that has multiple arguments -- VBO sends (as far as I know) only the object represented by each line in its table. However, using VBO to invoke rule sets without any arguments at all shouldn't be any problem.

Hm. I was just going to file an issue about this in the VBO queue, and found a discussion concerning this:
http://drupal.org/node/362537

//Johan Falk, Sweden